Application of the profiles of amino acid utilization as the sole carbon and nitrogen sources for pseudomonad taxonomy

Profiles of utilization of 20 amino acids were determined for 218 strains of 10 Pseudomonas species (P. aeruginosa, P. putida, P. fluorescens, P. stutzeri, P. alcaligenes, P. pseudoalcaligenes, P. luteola, P. oryzihabitans, P. mendocina, and P. chlororaphis), including the type strains of these species. Amino acid utilization was determined on minimal salt agar with an amino acid as the sole source of nitrogen and carbon. All the investigated pseudomonad species had species-specific profiles of amino acid utilization. For the type strains of all species, Jaccard’s coefficients of community were different (Sj = 0.31–0.82), in accordance with the interspecies differences. The similarity between the intraspecies variants of the profiles and that of the type strain was high; for 98% of P. aeruginosa strains, Sj = 0.85−1.0; for 100% of P. putida, P. stutzeri, and P. alcaligenes strains, Sj was 0.87–1.0, 0.90, and 0.86–1.0, respectively. Only for P. fluorescens and P. pseudoalcaligenes were low Sj of the intraspecies profiles revealed, in accordance with the known phenotypic heterogeneity of these species. These results agree with the known pseudomonad classification, and the method is therefore valid for identification of known species and for determination of the new members of the genus Pseudomonas.     

Pseudomonads from wild free-living sea turtles in Príncipe Island,Gulf of Guinea

Dissemination of antibiotic resistance is a major concern, especially in aquatic environments, where pollution contributes for resistant bacteria selection. These strains may have serious health implications, especially for endangered species, including the sea turtles’ hawksbill Eretmochelys imbricata and green turtles Chelonia mydas.We aimed to evaluate the presence of antibiotic resistant pseudomonads in wild sea turtles from Príncipe Island, São Tomé and Príncipe, Guinea Gulf. Isolates were obtained from oral and cloacal swabs of free-living turtles by conventional techniques. Pseudomonads screening was performed by multiplex-PCR (oprI/oprL) and biochemical identification and antibiotic resistance profiling were achieved using Vitek2. All pseudomonad isolates were genotyped by Rep-PCR.Thirteen isolates were oprI-positive and classified as pseudomonads, eight from the genus Pseudomonas with the species P. aeruginosa, P. stutzeri, and P. mendocina, and five co-isolated Alcaligenes faecalis. The P. aeruginosa isolate was also oprL-positive. Regarding isolates susceptibility profile, 38.5% were susceptible to all antibiotics tested, and multidrug resistant (MDR) strains were not identified. DNA fingerprinting did not show any specific clonal-cluster similarity.Data on the worldwide incidence of antibiotic resistance among wildlife is still very scarce, especially concerning remote tropical areas. Since Pseudomonas genus has emerged as a group of increasingly reported opportunistic microorganisms in human and veterinary medicine with high resistance levels, it could be used as a tool for environmental resistance surveillance, particularly considering their ubiquity.     

Immunochemical patterns of distribution of nitrous oxide reductase and nitrite reductase (cytochrome cd 1) among denitrifying pseudomonads

The novel multicopper enzyme nitrous oxide reductase from Pseudomonas perfectomarina was purified to homogeneity to study its properties and distribution in various pseudomonads and other selected denitrifying genera by immunochemical techniques. Quantitation of immunochemical crossreactivity by micro-complement fixation within the denitrifying pseudomonads of Palleroni's ribosomal ribonucleic acid group I corresponded to the taxonomic positions established by nucleic acid hybridization. The assignment of P. perfectomarina to the stutzeri-group (as strain ZoBell) was consolidated by immunochemical crossreactivity based on nitrous oxide reductase. Crossreactivity of nitrite reductase (cytochrome cd ₁) with a respective P. perfectomarina rabbit antiserum was limited to strain DSM 50227 of P. stutzeri; although it could not contribute information towards broader relationships within rRNA group I, it lent further prove to the unity of these two species.     

Studies of lipid A fractions from the lipopolysaccharides of Pseudomonas aeruginosa and Pseudomonas alcaligenes

Lipid A fractions from Pseudomonas aeruginosa and Pseudomonas alcaligenes have similar compositions and structural features. By means of hydrazinolysis of the parent lipopolysaccharides and partial hydrolysis of the deacylation products, it was established that both lipids are derived from the β-(1→6)-linked disaccharide of glucosamine. Phosphorylated derivatives of the disaccharide from Ps. aeruginosa were also characterized. The lipids differ mainly in the absence of hexadecanoic acid and 2-hydroxydodecanoic acid from the lipid from Ps. alcaligenes. Evidence that in Ps. aeruginosa these acids are ester-linked to residues of 3-hydroxyalkanoic acids (including 3-hydroxydecanoic acid) was obtained. Heterogeneity of lipid A fractions was indicated by t.l.c., and by gel filtration of de-O-acylation products from mild alkaline methanolysis of the lipids.     

Preliminary Studies of Fluorescent Pseudomonads Capable of Growth at 41 C in Swimming Pool Waters

During the summer of 1973 cultures of Pseudomonas aeruginosa and other fluorescent pseudomonads capable of growth at 41 C were obtained from swimming pool waters at a training center for the mentally retarded. Isolates were subjected to selected physiological tests, pyocine typing, and immunotyping. High counts of P. aeruginosa or other fluorescent pseudomonads consisted mainly of single predominant types. Both P. aeruginosa strains and unidentified fluorescent Pseudomonas strains predominated in pool waters at different times.     

Triclosan-Induced Modification of Unsaturated Fatty Acid Metabolism and Growth in Pseudomonas aeruginosa PAO1

Triclosan is a broad-spectrum antimicrobial agent having low toxicity which facilitates its incorporation into numerous personal and health care products. Although triclosan acts against a wide range of gram-positive and gram-negative bacteria by affecting fatty acid biosynthesis, it is ineffective against the opportunistic pathogen Pseudomonas aeruginosa. Wild-type strain P. aeruginosa PAO1 was used as a model system to determine the effects of triclosan on fatty acid metabolism in resistant microorganisms. This was accomplished by cultivating P. aeruginosa PAO1 cultures in the presence of different concentrations of triclosan, monitoring growth rates turbidimetrically, and harvesting in stationary phase. Readily extractable lipids (RELs) were obtained from freeze-dried cells after washing and analyzed using gas chromatography coupled with mass spectrometry. Resultant data demonstrated that triclosan caused dose-dependent increases in the amounts of trans-C_16:1 and trans-C_18:1 fatty acids, with concomitant decreases in their respective cyclopropyl analogs. Triclosan did not affect the relative concentrations of saturated, cis unsaturated, or the overall ratios of combined C₁₆ to C₁₈ fatty acid species. The readily extractable lipid fractions contained triclosan proportional to triclosan concentrations in the growth media. The presence or absence of triclosan in either liquid or solid media did not affect the antimicrobial susceptibilities of P. aeruginosa PAO1 to a battery of unrelated antimicrobials. Triclosan decreased growth rate in a dose-dependant manner at soluble concentrations. Incorporation of triclosan into the REL fraction was accompanied by increased levels of trans unsaturated fatty acids, decreased levels of cyclopropyl fatty acids, and decrease in growth rate. These alterations may contribute to triclosan resistance in P. aeruginosa PAO1.     

Reversal of the Vancomycin Inhibition of Peptidoglycan Synthesis by Cell Walls

Addition of cell walls to the peptidoglycan synthetase-acceptor system containing vancomycin (50 μg/ml) prevented the inhibition by the antibiotic. In addition, the inhibition of incorporation of [¹⁴C]muramyl-pentapeptide into peptidoglycan in the presence of vancomycin was reversed by the addition of cell walls to the assay mixture at 60 min. Cell walls previously saturated with vancomycin lost their ability to reverse the inhibition by the antibiotic. The inhibition of peptidoglycan synthesis by ristocetin was partially reversed by the addition of cell walls. The initial stage in peptidoglycan synthesis is catalyzed by phospho-N-acetyl(NAc)muramyl-pentapeptide translocase (uridine 5′-phosphate) according to the reaction: UDP-NAc-muramyl-pentapeptide + acceptor acceptor-phospho-NAc-muramyl-pentapeptide + UMP where acceptor is C₅₅-isoprenoid alcohol phosphate. Vancomycin stimulates the transfer of phospho-NAc-muramyl-pentapeptide to the acceptor, and the addition of cell walls to this assay mixture prevented the stimulation of transfer. In addition to the transfer reaction, the enzyme catalyzes the exchange of [³H]uridine monophosphate (UMP) with UDP-NAc-muramyl-pentapeptide. The exchange reaction is effectively inhibited by vancomycin. For example, 60 μg of vancomycin per ml inhibited the rate of exchange by 50%. Addition of cell walls restored the exchange of UMP with the UMP moiety of UDP-NAc-muramyl-pentapeptide. Thus, cell walls appeared to have a higher affinity for vancomycin than did either the peptidoglycan synthetase-acceptor system or phospho-NAc-muramyl-pentapeptide translocase. These results provide support for the proposal made by Best and Durham that the effective binding of vancomycin to the cell wall could result in the inhibition of transfer of membrane-associated peptidoglycan chains to the growing wall.     

The occurrence of Pseudomonas spp. in surface water and in tap water as determined on citrate media

Citrate-utilizing bacteria were counted in 289 samples of tap water derived from either surface water or ground water and in 32 samples of raw or partially treated surface water by using media containing ferric ammonium citrate as the carbon and energy source.The citrate-utilizing bacteria constituted only small minorities of the colony counts on Lab-Lemco agar at 25 C in both tap water and surface water.A total of 1071 isolates were obtained, of which 979 were able to utilize citrate. Characterization of the citrate-utilizing isolates revealed that 90% of these bacteria were arginine dihydrolase-positive and belonged to the genera Pseudomonas (84.3%) and Aeromonas (5.7%).The genus Pseudomonas was represented by fluorescent pseudomonads (66.3%), non-fluorescent glucose-utilizing pseudomonads (12.1%) and P. alcaligenes (5.9%). None of the isolates was identified as P. aeruginosa.It is suggested that the pseudomonads and the aeromonads are not adapted to low substrate concentrations. Enumeration of the citrate-utilizing bacteria in tap water therefore may give information on the efficiency of water treatment techniques as regards the substrate removal.     

Identification of Eubacteria Isolated from Leaf Cavities of Four Species of the N-Fixing Azolla Fern as Arthrobacter Conn and Dimmick

The nutritional and physiological characteristics of 15 isolates from four species of the Azolla fern were determined. Although some minor variation existed in levels of urease activity, ability to utilize xylose, and formation of N₂ gas from NO₃, all 15 isolates were rather similar and believed to represent a single species. These eubacteria exhibited aminopeptidase activity and became viscous when treated with KOH, similar to gram-negative organisms; however, the absence of lipopolysaccharide and 2-keto-3-deoxyoctonate in cell walls indicated that they are truly gram-positive organisms. They are unusual because peptidoglycan could not be detected during most of their growth cycle. The presence of lysine as the major diamino acid in cell wall hydrolysates, the inability to hydrolyze cellulose, and the distinctive developmental pattern with rods and “V” forms present during log phase, becoming progressively shorter until cocci dominated during stationary and death phases, indicated that these organisms belong to the genus Arthrobacter Conn and Dimmick. With the exception of the inability to hydrolyze gelatin, their characteristics are consistent with those of the type species, Arthrobacter globiformis Conn and Dimmick.     

Effect of aerobic and anaerobic growth on the cell wall ofStaphylococcus aureus

Electron micrographs ofStaphylococcus aureus 7167 which had been grown anaerobically showed that the cell wall was approximately 5 times thicker than the wall of bacteria after aerobic growth. Cell walls prepared from anaerobically grownS. aureus were more sensitive to the bacteriolytic enzymes: lysostaphin, lysozyme, and the wall-associated autolytic enzyme ofB. subtilis 168 I^?. Our findings are interpreted as evidence that the cell wall or surface of anaerobically grownS. aureus 7167 is different from that of aerobically grownS. aureus 7167. The findings suggest that the cell wall peptidoglycan of the anaerobe is a more loosely formed network, resulting in a more rapid solubilization by the bacteriolytic enzymes.     

Quantitative Analysis of Actinomyces Cell Walls

Quantitative data on the amino acid composition of cell walls of five species of Actinomyces were obtained by using a Beckman-Spinco amino acid analyzer. The major amino acids in A. israelii, A. naeslundii, A. eriksonii, and A. bovis species included alanine, glutamic acid, lysine, aspartic acid, and ornithine, as reported by previous workers, whereas A. propionicus contained diaminopimelic acid. Other amino acids, including glycine, valine, leucine, proline, isoleucine, and threonine, were present in at least some of the walls in quantities equal to or slightly less than that of lysine. This raised the question of whether these may represent cross-links in the peptidoglycan or other cell wall structural components or whether the wall preparations contained nonpeptidoglycan material despite the use of electron microscopy as a standard of purity; further work is required to supply the answer. The quantitative data furnish relative molar concentrations of amino acids, which can provide definitive identification of some of the species and differentiation of Actinomyces from other members of the Actinomycetales and from morphologically similar genera such as Corynebacterium and Propionibacterium.     

Studies of Pseudomonas aeruginosa Infections Among Hospitalized Patients

A rapid identification method of glucose nonfermentative gram-negative rods was established and 320 strains isolated were divided into five groups according to their characteristics in pigmentation, acid from glucose, cytochrome oxidase activity and motility. Further characterization of the strains in each group resulted in the identification that the strains in group I were Pseudomonas aeruginosa, strains in group II, P. aeruginosa and Pseudomonas putida. Achromogenic strains of P. aeruginosa were classified into group III, Pseudomonas maltophilia, Pseudomonas alcaligenes and Alcaligenes faecalis into group IV and Acinetobacter calcoaceticus (Acinetobacter anitratus and Achromobacter lwoffii) in group V. When fluorescent pigment production was taken as a standard, 259 out of 263 chromogenic strains were identified as P. aeruginosa and the remaining four were P. putida. Whereas forty-five achromogenic strains included twenty-four A. calcoaceticus, eight P. aeruginosa, six A. faecalis, five P. maltophilia and two P. alcaligenes. From May 1970 to June 1971, 368 strains of glucose nonfermentative rods were isolated from clinical specimens sent to the Central Laboratories of Tohoku University Hospital and three fourth (286/368) of the isolates were P. aeruginosa     

S-Layered Aneurinibacillus and Bacillus spp. Are Susceptible to the Lytic Action of Pseudomonas aeruginosa Membrane Vesicles

When S-layered strains of Bacillus stearothermophilus and Aneurinibacillus thermoaerophilus, possessing S-layers of different lattice type and lattice constant as well as S-(glyco)protein chemistry, and isogenic S-layerless variants were subjected to membrane vesicles (MVs) from P. aeruginosa during plaque assays on plates or CFU measurements on cell suspensions, all bacterial types lysed. Electron microscopy of negative stains, thin sections, and immunogold-labelled MV preparations revealed that the vesicles adhered to all bacterial surfaces, broke open, and digested the underlying peptidoglycan-containing cell wall of all cell types. Reassembled S-layer did not appear to be affected by MVs, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that the S-(glyco)proteins remained intact. meso-Diaminopimelic acid, as a peptidoglycan breakdown product, was found in all culture supernatants after MV attack. These results suggest that even though MVs are much larger than the channels which penetrate these proteinaceous arrays, S-layers on gram-positive bacteria do not form a defensive barrier against the lytic action of MVs. The primary mode of attack is by the liberation from the MVs of a peptidoglycan hydrolase, which penetrates through the S-layer to digest the underlying peptidoglycan-containing cell wall. The S-layer is not affected by MV protease.     

Antimicrobial Properties of Pyridine-2,6-Dithiocarboxylic Acid, a Metal Chelator Produced by Pseudomonas spp.

Pyridine-2,6-dithiocarboxylic acid (pdtc) is a metal chelator produced by Pseudomonas spp. It has been shown to be involved in the biodegradation of carbon tetrachloride; however, little is known about its biological function. In this study, we examined the antimicrobial properties of pdtc and the mechanism of its antibiotic activity. The growth of Pseudomonas stutzeri strain KC, a pdtc-producing strain, was significantly enhanced by 32 μM pdtc. All nonpseudomonads and two strains of P. stutzeri were sensitive to 16 to 32 μM pdtc. In general, fluorescent pseudomonads were resistant to all concentrations tested. In competition experiments, strain KC demonstrated antagonism toward Escherichia coli. This effect was partially alleviated by 100 μM FeCl₃. Less antagonism was observed in mutant derivatives of strain KC (CTN1 and KC657) which lack the ability to produce pdtc. A competitive advantage was restored to strain CTN1 by cosmid pT31, which restores pdtc production. pT31 also enhanced the pdtc resistance of all pdtc-sensitive strains, indicating that this plasmid contains elements responsible for resistance to pdtc. The antimicrobial effect of pdtc was reduced by the addition of Fe(III), Co(III), and Cu(II) and enhanced by Zn(II). Analyses by mass spectrometry determined that Cu(I):pdtc and Co(III):pdtc₂ form immediately under our experimental conditions. Our results suggest that pdtc is an antagonist and that metal sequestration is the primary mechanism of its antimicrobial activity. It is also possible that Zn(II), if present, may play a role in pdtc toxicity.     

Molecular cloning of genenahH encoding extradiol-type dioxygenase from the NAH plasmid ofPseudomonas stutzeri NA1

Naphthalene-degradingPseudomonas stutzeri NA1 was found to harbour the NAH plasmid, which contains the classical upper and lower catabolic genes required for naphthalene mineralization. The lower pathway inP. stutzeri NA1 was found to proceedviameta-ring cleavage of catechol due to the presence of thenahH gene encoding extradiol catechol 2,3-dioxygenase. Naphthalene-induced cells were able to mineralise both salicylate and catechol. Absorption spectra and gas chromatography/mass spectrometry analysis ofritermediate metabolites of salicylate or catechol degradation by a crude extract ofP. stutzeri NA1 revealed the presence of themeta-ring cleavage product 2-hydroxymuconate semialdehyde as a major constituent. The extradiol ring cleavage genenahH was amplified successfully from the NAH plasmid ofP. stutzeri NA1 with catechol 2,3-dioxygenase-specific primers and cloned inEscherichia coli JM109 The complete nucleotide sequence of cloned PCR fragment was determined. Sequence analysis of cloned PCR fragment revealed an open reading frame with similarity to other extradiol dioxygenases. The deduced amino acid sequence ofnahH fromP. stutzeri NA1 showed 96% sequence identity with the catechol 2,3-dioxygenase gene fromPseudomonas putida strain H. However, when compared to othernahH genes from different pseudomonads, it was in a separate phylogenetic branch, indicating a degree of speciation among the extradiol dioxygenase family.     

X-ray Diffraction Studies of Cell Walls and Peptidoglycans from Gram-positive Bacteria

THE cell walls of Gram-positive bacteria consist principally of a water-insoluble polymer and peptidoglycan (synonyms, murein, mucopeptide, glycosaminopeptide), which in some cases accounts for as much as 90% of the cell wall. After other components (teichoic acid, teichuronic acid, polysaccharide or protein) have been gently removed from the cell walls, peptidoglycan remains as a cell-shaped structure at least 100 Å thick. We report here results of X-ray diffraction observations on whole cell walls and peptidoglycans of Staphylococcus aureus, Bacillus licheniformis and Micrococcus lysodeikticus. Chemical data shows that all the muramic acid residues in the glycan chains of the peptidoglycan of S. aureus are substituted with the peptide L Ala-D GluNH₂-L Lys-D Ala and that there is extensive cross linking by pentaglycine bridges between peptides on adjacent glycan chains^1,3. Such a peptidoglycan might be expected to have an ordered crystalline structure. On the contrary, peptidoglycans of the bacilli, in which the cross linking between peptides is direct and considerably less^4,5 might be expected to have a less ordered structure. The mode of packing of the glycan and peptide moieties has been considered by Kelemen and Rogers⁶. When the glycan chains are stacked in pairs, as in the analogous polysaccharide chitin⁷, the muramic acid residues are orientated in such a way as to allow a three-dimensional structure to be built. If the bulk of the peptides are then arranged in a pseudo β configuration, calculations show that the expected dimensions of the cell wall calculated from the model are of the right order and also such a model allows for the existence of extensive stabilizing hydrogen bonds between adjacent peptide chains.     

Protective activities of ribosomal ribonucleic acid and lipopolysaccharide of Pseudomonas aeruginosa: a comparative study

Ribosomal ribonucleic acid (RNA) and lipopolysaccharide (LPS) from P. aeruginosa were compared with respect to their protective activities in mice against an infection with P. aeruginosa. This study is concentrated on the protective activity of RNA. RNA isolated from purified ribosomes did not contain LPS as determined with the Limulus test. Injection of RNA with the adjuvant dimethyldioctadecylammonium bromide (DDA) protected mice against P. aeruginosa without inducing LPS-specific antibodies. C₃H/HeJ mice which are relatively insensitive to the protective activity of LPS could be protected with RNA. The protective activities of RNA and LPS from a mutant strain of P. aeruginosa, PAC 605, containing defective lipopolysaccharide, were compared with the protective activities of RNA and LPS from the parent strain, PAC IR. The protective activity of LPS from PAC 605 was 1000 fold lower than the protective activity of LPS from PAC IR. RNA preparations of both strains induced similar percentages of survival. The protective activity of ribosomal RNA from P. aeruginosa was nonspecific since mice were also protected against a heterologous serotype of P. aeruginosa and against Escherichia coli. RNA from ribosomes of P. aeruginosa, E. coli and the non-lipopolysaccharide containing Saccharomyces cerevisiae had similar protective activities. No protection was obtained with the ribonucleic acid from the E. coli phage MS 2. It is concluded that ribosomal RNA has protective activities distinct from those of LPS.     

Photosynthesis of Grass Species Differing in Carbon Dioxide Fixation Pathways : VIII. Ultrastructural Characteristics of Panicum Species in the Laxa Group

Ultrastructural studies of leaves of seven Panicum species in or closely related to the Laxa group and classified as C₃, C₄ or C₃-C₄ intermediate were undertaken to examine features associated with C₃ and C₄ photosynthesis. The C₃ species Panicum rivulare Trin. had few organelles in bundle sheath cell profiles (2 chloroplasts, 1.1 mitochondria, and 0.3 peroxisomes per cell section) compared to an average of 10.6 chloroplasts, 17.7 mitochondria, and 3.2 peroxisomes per bundle sheath cell profile for three C₃-C₄ species, Panicum milioides Nees ex Trin., Panicum decipiens Nees ex Trin. and Panicum schenckii Hack. However, two other C₃ species, Panicum laxum Sw. and Panicum hylaeicum Mez, contained about 0.7, 0.5, and 0.3 as many chloroplasts, mitochondria, and peroxisomes, respectively, as in bundle sheath cell profiles of the C₃-C₄ species. Chloroplasts and mitochondria in bundle sheath cells were larger than those in mesophyll cells for the C₄ species Panicum prionitis Griseb. and the C₃-C₄ species, but in C₃ species the organelles were similar in size or were smaller in the bundle sheath cells. The C₃-C₄ species and P. laxum and P. hylaeicum exhibited an unusually close association of organelles in bundle sheath cells with mitochondria frequently surrounded in profile by chloroplasts. The high concentrations in bundle sheath cells of somewhat larger organelles than in mesophyll cells correlates with the reduced photorespiration of the C₃-C₄ species.     

Kytococcus aerolatus sp. nov., isolated from indoor air in a room colonized with moulds

A Gram-positive, coccoid bacterial isolate (02-St-019/1^T), forming beige pigmented colonies was obtained from an indoor air sample. Based on 16S rRNA gene sequence similarity studies it was determined that this isolate 02-St-019/1^T belonged to the genus Kytococcus, showing sequence similarties of 98.6% to Kytococcus schroeteri DSM 13884^T and 98.3% to Kytococcus sedentarius DSM 20547^T, respectively. The diagnostic diaminoacid of the peptidoglycan was lysine, cell wall sugars were ribose and xylose. The major menaquinones detected were MK-7 and MK-8. The polar lipid profile consisted of the major phospholipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine and phosphatidylinositol mannoside. Fatty acid patterns were composed of major amounts of the iso- and anteiso-branched fatty acids anteiso C_17:0, iso C_15:0 and iso C_17:0 and unsaturated fatty acids (C_17:1 ω8c, iso C_17:1 ω9c, and C_17:1 ω8c) with smaller amounts of the straight-chain fatty acids C_15:0, C_16:0 and C_17:0. The results of DNA–DNA hybridizations and physiological and biochemical tests clearly allowed a genotypic and phenotypic differentiation of strain 02-St-019/1^T from the two described Kytococcus species. On the basis of these results a novel species to be named Kytococcus aerolatus sp. nov., is proposed, with the type strain 02-St-019/1^T (=DSM 22179^T=CCM 7639^T).     

Enzymes Lytic against Pseudomonas aeruginosa Produced by Bacillus subtilis YT-25

A bacterium YT–25 which produces enzymes lytic against Pseudomonas aeruginosa was isolated from soil and it was identified as Bacillus subtilis.

A₁-enzyme, A₂-enzyme, B-enzyme and NLF (Native Cell-Lytic Factor) which contribute the lysis of P. aeruginosa were purified from the culture filtrate of strain YT–25.

Purified A₁-enzyme, A₂-enzyme and B-enzyme individually lysed the vegetative cells of P. aeruginosa in the presence of NLF.

NLF is a low molecular basic peptide and seemed to alter the sufrace structure of P. aeruginosa.

B-enzyme hydrolyzed the peptidoglycan purified from P. aeruginosa to release the reducing groups, but A₁-enzyme and A₂-enzyme released neither reducing groups nor free amino groups from the peptidoglycan.